1. Field of the Invention
This invention relates to an improved air brush and relates in particular to an air brush maintaining an air blow quantity correctly matching the amount of paint blow from the nozzle by a simple operation when drawing fine and superfine lines.
2. Description of Related Art
An airbrush 100 of the prior art has a long, cylindrical air brush main body 101 with a nozzle 102 installed at the tip (extremity) as shown in FIG. 13 and FIG. 14. A needle 103 is provided to freely advance and retract along the center axis within the air brush main body 101. The air brush 100 is structured so that compressed air is supplied to an air supplying port 104 connected to the center of the air brush main body 101. This compressed air is supplied to an aeration passage 112 within the air brush main body 101 by way of an air valve 105 and is blown out from the nozzle 102. The air valve 105 is also configured to open when the operating lever 105a is pressed.
In the air brush 100, a pushing lever 108 for depression is connected by way of a pivot shaft 107 to the bottom of the operating lever 106 fitted into the intermediate section of the upper surface of the air brush main body 101. The pushing lever 108 is inserted into the insertion hole 109 inside the main body 101 so that the pushing lever 108 is thus supported and slides along the axis along with the operating lever 106. The tip (extremity) of the pushing lever 108 contacts the tip of the air valve rod 105a of the air valve 105. An operating button 106a for placement of the user""s finger, is formed on top of the operating lever 106.
A valve rod 105a is installed inside the connecting cylinder 110 forming the air supplying port, and the force of a coil spring 111 applies a constant upward force so that the upper end of the valve rod 105a is maintained in contact with the tip (extremity) of the pushing lever 108 (FIG. 13, FIG. 14).
When the user depresses the operating lever 106, the valve rod 105a is depressed by way of the pushing lever 108, and the air valve 105 opens. The compressed air from the air compressor or compressed air source connected to the connecting cylinder 110 is thus supplied into the main body 101 of the air brush, and is blown out from the nozzle 102 by way of an aeration passage 112.
When the user pulls the depressed operating lever 106 further rearward, tilting on the pivot point of the pivot shaft 107, a needle 103 supportably held in a needle chuck 113 moves backward, and the paint supply from the paint container 112 is atomized into a mist by the blowing of compressed air. An operation of this kind that pulls on the operating lever 106 after depressing is called double-action. The spraying of paint is performed by double-action in most cases.
When drawing a fine line by using the air brush 100 of the above described prior art, the operating lever 106 is pushed down and air is blown from the nozzle 102. Next, this same operating lever 106 is pulled back slightly while still depressed, and a small quantity of paint is supplied to the nozzle 102 and a fine line can be drawn. In other words, the paint is applied by double-action of the operating lever 106.
To write a fine line with good appearance by using the air brush 100, the operating lever 106 (needle 103) is pulled back slightly while keeping this same operating lever 106 just slightly depressed, so that a fine line with good appearance and uniform thickness can be drawn. However, this operation of pulling back just slightly on the operating lever 106 while keeping it slightly depressed is difficult even for a veteran and drawing fine lines of uniform thickness while maintaining this position, in particular for drawing super-fine lines is only possible for an extremely limited number of people.
In other words, in order to draw a fine line, most users press the operating lever 106 all the way to the bottom at a maximum air blow quantity, and pulled on the operating lever 106 just a little to draw a fine line with a small paint quantity. Consequently, spots or scattering such as in flower-shaped patterns occurred at the first air blow (See the graph of FIG. 10 and test pattern of FIG. 11.). The air blow quantity was also large compared to the quantity of paint being supplied, so that when fast-drying paint was used, the tip (extremity) of the nozzle 102 became extremely dry, dry paint adhered to the needle 103, the quality of the drawn line deteriorated and omission (paint cut off) points occurred. In worst cases the nozzle 102 became completely clogged.
The air brush of the prior art therefore emitted different air blow quantities when drawing fine and super-fine lines, requiring the user to possess a plurality of air brushes (having different nozzle diameters).
In view of the above mentioned problems with the prior art, this invention has the object of providing an air brush capable of drawing fine lines and in particular super-fine lines in a small blow-out area, maintain an ideal proportion of air and paint spray quantities from the nozzle, and draw smoothly without spots, ink scattering or omissions.
In order to resolve the above mentioned problems, this invention is configured with a needle moving forwards and backwards along the center axis of an air brush body of a roughly long and cylindrical shape. The needle opens and closes a nozzle formed at the tip (extremity) of the airbrush. An air blow of compressed air is supplied from this nozzle by way of an air valve inside the air brush body. An operating lever is formed inside the air brush at the upper surface. A pushing lever is freely depressed by pivot shaft formed at the bottom of the operating lever and the pushing lever is freely supported along the operating lever for free up and down movement. The bottom of this pushing lever pushes on the top edge of the valve rod that opens and closes the air valve. The valve rod is push-activated by the operating lever and along with opening the air valve, tilts the operating lever rearwards, and makes the needle linked to the operating lever move backwards along the axis of the air brush body. The air brush is configured to atomize the paint supplied to the nozzle by blowing compressed air. A support piece is formed extending forwards from the operating button on the top of the operating lever. A through rod is vertically inserted in an insertion hole in the support piece. A contact piece is attached extending in parallel with the air brush body facing rearward from the bottom of the through rod. A locking mechanism is provided to clamp the through rod in any desired position or support the through red for up and down movement, and the bottom surface of the contact piece may contact with and separate from the top surface of the air brush main body.
In the means described above, pressing the button of the operating lever, causes the valve rod of the air valve to be depressed by way of the pushing lever, and thus open the air valve, supply compressed air into the inside of the air brush, and blow the compressed air from the nozzle. Also, pulling the operating lever rearwards while still depressed, moves the needle inserted along the axial core of the air brush body rearwards. The nozzle is thus opened and paint supplied and the paint is atomized into a mist by the air blow (in the case of double-action).
When drawing fine lines and especially super-fine lines using the air brush, the through rod lowers in the support piece, in a state with the operating lever aligned with the stationary closed valve position, the contact piece formed in the lower end of the through rod makes light contact with the upper edge of the air brush main body. The through rod is clamped to the support piece formed in the operating button and this state is maintained by utilizing a lock mechanism, and the through rod and the contact piece are held so that no movement or play (looseness) occurs.
When the button of the operating lever is slightly pressed while in this state, the operating lever tilts rearward slightly and is depressed sliding rearwards though only a slight amount. The extended tip (rear end) of the contact piece formed in the bottom of the through-rod at this time slides gradually to the rear to the top surface of the air brush main body. At initial movement of the start button, the pivot point supporting the tilt movement of the operating lever, shifts from the pivot section at the bottom of the operating lever, to the extended tip of the contact piece contacting the upper surface of the air brush, and the operating lever then tilts using the extension tip as the pivot point.
In other words, the range (range for drawing super-fine lines and fine lines) that the extension tip of the contact piece makes contact with the upper surface of the air brush main body and slides rearward, increases in proportion to the amount the operating lever is pulled and the amount the operating lever is depressed (single-action). The range for drawing the fine and super-fine lines therefore be increased or decreased while maintaining a suitable ratio between the quantity of air blown from the nozzle and paint supply. In other words, the initial range of the operating lever movement allows single-action dispensing (blow) of a satisfactory quantity of air matching the supply and characteristics of the paint and fine lines can be drawn smoothly and with uniform thickness.
When the operating lever is further pressed from the range used for drawing fine lines, the extension tip of the contact piece moves away (separates) from the air brush main body upper surface and the pivot point of the operating lever returns to the pivot section of the bottom of that same operating lever. The spraying of lines can then be performed with the same characteristics obtained from a conventional air brush.
In the air brush according to second aspect of the invention, a support piece is installed extending forwards from an operating button formed on top of the operating lever, a screw shaft constituted by a male screw is vertically screwed into a screw hole drilled in the support piece, the bottom edge of the screw shaft is fastened to the center of a contacting knob formed in a circular shape seen from a flat plane, and rotation of the screw shaft causes the lower surface of the same contact piece to supportably contact with and separate from the top surface of an air brush main body, and further, the upper edge of the screw shaft pushes against the top edge of the support piece, and a lock screw comprised of a female screw, engages with the top edge of the screw shaft, to make pressure-contact with and separate from the top surface of the contact piece.
The function of the air brush according to second aspect of the invention is related in the subsequent description (preferred embodiments).